Egypt has a new president, a longtime judge who took the oath of office this morning. That official change in power came after several days of protests saw millions of Egyptians pour into the streets, demanding Mohamed Morsi step down. His refusal led to his ouster yesterday by Egypt's military. It was a stunning turnaround for the country's first democratically elected president.

GREENE: He and of other Muslim Brotherhood leaders have now been detained, and Egypt is divided, with those against Morsi celebrating and his supporters mourning what they call the death of democracy

MONTAGNE: For the latest, we go to NPR's Soraya Sarhaddi Nelson, who is in Cairo. And, Soraya, a lot of news there, but tell us first about this new interim president. I gather he does not have any sort of political following.

SORAYA SARHADDI NELSON, BYLINE: He definitely doesn't. He's relatively unknown, but he is a lawyer with more than 40 years experience. His name is Adly Mansour. He's 67 years old, and he just started his term as the head of the Supreme Constitutional Court on Tuesday. And the swearing-in was delayed until this morning. Of course, the people who are now sort of in charge of Egypt say that was purposefully delayed by Mohamed Morsi, the now-deposed president.

MONTAGNE: And the military, why is it going so aggressively after the Islamists at this point, the Muslim Brotherhood leaders?

NELSON: Well, there are varying thoughts, depending on what side of this equation you're talking to. But certainly, the military has expressed great concern about keeping the peace and limiting bloodshed. And because the Islamists and the supporters of deposed President Morsi have been talking about resisting this takeover, if you will - with their lives if necessary - the fear is that, you know, if they don't take care of these or if they don't go after these leaders, that somehow resistance or a backlash will be organized.

But on the other side of the equation, certainly, the Muslim Brotherhood and others are saying that this is basically a return to the enmity of the past, where the military has always had conflict with the Islamists here for decades, and that they're basically just trying to get them all now and ban them, put them underground, whatever the case might be.

MONTAGNE: And now the protesters out on the streets are from the Muslim Brotherhood. Are those protests continuing?

NELSON: Well, they are still out there. The question is will they stay out there in large numbers, given the fact that the military is aggressively going after the Brotherhood leadership, you know, officials associated with the deposed president. The soldiers are out there with a very sort of ominous, terse presence around these rallies that are being held by Morsi supporters and Muslim Brotherhood supporters. So it's a question about whether they'll be able to maintain that momentum, as they claimed they would do.

MONTAGNE: And President Obama has come out and expressed grave concerns about this coup, and also the military's treatment of the Islamists. What is the reaction there in Egyptian to his statement?

NELSON: Well, both sides are very unhappy with the Obama administration, and for them, the statement comes too late. In the case of the Muslim Brotherhood, they feel that the American administration has a very strong relationship with the Egyptian military, gives them billions of dollars in aid, and that sort of thing. And certainly, the Morsi people have said all along that they didn't feel a coup could happen without tacit American support.

And on the other side, you have the anti-Morsi people who feel that the Americans were far too cozy with the Muslim Brotherhood. And so they feel that - especially with statements like this - that the United States, or that the Obama administration is not on their side.

MONTAGNE: Well, we'll be hearing more about this as the morning goes on. NPR's Soraya Sarhaddi Nelson, speaking to us from Cairo .Thank you very much.